Ocular surgery frequently involves the removal of fluid and/or tissue from the eye via an aspiration line and replacement of the material removed with fluid provided by an irrigation or infusion line. The aspiration line is coupled to tubing that is connected to a vacuum pump controlled by a console. Similarly, the infusion line is connected to a fluid source via tubing.
During surgery, a cannula connected to the aspiration line is inserted into the patient's eye. To activate the vacuum pump, the surgeon may depress a foot pedal. Pressing the foot pedal through a particular angle causes a vacuum to ramp up to a particular set point. For example, depressing the foot pedal by a particular number of degrees may cause the vacuum pump to provide a vacuum level of −600 mm Hg (millimeters of mercury) (a pressure less than the ambient pressure by 600 mm Hg). This vacuum is applied to the aspiration line in order to remove material from the eye. Fluid may also be provided to the eye via the infusion line to allow the intraocular pressure of the eye to be maintained.
Although the ophthalmic surgery may be performed, patient health may be adversely affected. For example, if the foot pedal is aggressively depressed an amount corresponding to a high vacuum, material may rapidly flow out of the eye. This flow of material may be too fast for fluid from an infusion line to immediately compensate. Consequently, the intraocular pressure may quickly decrease. Eventually, the inflow of fluid from the infusion line returns the intraocular pressure to be within a desired equilibrium range. However, the transient drop in intraocular pressure may still be unsafe for the patient.
Accordingly, what is needed is a mechanism for reducing transient decreases in intraocular pressure.